Sonic S O U N D W A V E
by Snazzyart
Summary: When Eggman successfully collects all seven of the Chaos Emeralds, he uses their power to activate a portal? What could he gain from that? Sonic and his friends find themselves racing in a world of lights and music, searching for the emeralds once again.
1. Chapter 1

**DISCLAIMER; I do not own any Sonic character or any related terms. All characters used and certain mentions © SEGA/SONIC TEAM**

**The only thing I can claim right is the general idea and Tempo the Dog. **

_**A/N: This is an idea that's been lingering in my brain for the longest time, which was to combine music into an adventure Sonic the Hedgehog could embark on. Reviews are helpful; I need all the feedback I can get in order to see if this is appealing or not. For now, I hope you the beginning of SONIC S O U N D W A V E. **_

Prologue

"Sonic!" shouted a young, twin-tailed fox; obviously exasperated. "Eggman has collected all of the Chaos Emeralds! We have to move!" he jabbed a finger rapidly against a small device that located the emeralds, which beeped endlessly. The cobalt hedgehog in front of him shook his head in a daze.

"There's no way he could've gotten them all that quickly," he muttered in disbelief, "Tails is right! We've got to get to him _now_!"

"Well, let's go! It beats standing around and complaining!" a red echidna perked up rashly. They all hopped into a plane, where the fox addressed as Tails managed the controls. Both the echidna and hedgehog stood on the wings of the blue-and-yellow plane, nodding towards the fox to proceed in takeoff.

"Alright guys – to Eggman's base!" Tails announced, the plane lifting into the sky and flying away.

CHAPTER ONE

Sonic jumped off the wing of the plane, diving down towards one of the flying robots that targeted him from above. He began spinning quickly in a tight ball, dashing into the robot as if a piece of paper. The aerial robot crashed onto rough land, where Eggman's base could be found. The hedgehog landed on the ground, kneeling down in the process.

"Down here, guys!" he called, the plane 'Tornado' beginning to land beside Sonic. The red echidna, Knuckles, glided down to his side and asked, "We're heading in, right?"

Sonic smirked. "Well duh! Though I think I might need you and Tails to help out with the direct fleet," he stated, "I'm heading for the core before Eggman can do anything with the Chaos Emeralds."

Tails nodded, listening into their conversation. "You better hurry, Sonic, these robots are coming by the dozens!"

"Right!" Sonic exclaimed, "You two take care! This shouldn't take long!" he remarked as he bolted inside through a crowd of robots, all of them taking aim towards him. Knuckles began punching his way through while Tails, inside the Tornado, started launching missals.

"He better get to Eggman quick!" Knuckles grunted as he fought, "He always has something up his sleeve."

"We're going to have to trust him, Knuckles," Tails replied, struggling to aim properly with the robots' numbers growing, "He'll pull something off, I know it."

* * *

><p>Sonic pushed his way through several backup forced, either hopping over them or fighting them directly. To his benefit, they increased his willpower as the cobalt hedgehog advanced forward quickly. <em>"Huh, this is a lot,"<em> he thought to himself, finding this base much more complicated compared to his previous intrusions.

Sonic, soon thereafter, arrived at a large set of silver doors- which obviously gave away the entrance to the main control room. "He never changes, does he?" he commented to himself as he broke them open. He quickly spotted Eggman typing several commands into a computer, which sent signals to the emeralds that sat in individual columns protected by a layer of thick glass.

"I'm afraid you're too late, Sonic!" the man bellowed, "The emeralds are already in my control."

"If I had a nickel for _every _time we've been in this situation, I'd live in a mansion!" Sonic chortled sarcastically, crossing his arms. "Just what do you think you're gonna do? _Vanquish _me?"

"I don't have time for your child's play, Sonic; I'm too busy opening a portal!" he stated loudly, dramatically pressing a bright red button. The energy emitting from the emeralds began channeling through small, transparent pipes towards two, large arches.

"A portal? That seems a bit familiar, don't you think?" the hedgehog said, rather puzzled, as he stared at the machine.

"Hohoho!" Eggman laughed, "I'm afraid _this _portal is much different!" A bright violet aura began gathering between the arches, a large mass of energy sucking up nearby objects. To Eggman's surprise, the emeralds themselves began disappearing, their energy causing a huge disruption in the system.

"Wha?" Eggman shouted, "What _is _this?" The man shot up from his chair and chased after the energy, _inside _the portal.

"Eggman?" Sonic yelped, watching as Eggman's figure fell deeper into the portal, soon vanishing from plain sight. Tails and Knuckles approached the hedgehog from behind, both of them visibly shocked.

"Sonic? Where's Eggman- and what is this?" Knuckles demanded, clenching his spiky fists.

"He just threw himself into this portal! He used the emerald's power to function this thing, and they just disappeared once the portal opened up!"

"H-How is that so?" Tails stammered, "That's never happened before! This must mean that the emeralds have overpowered the mechanics of this machine; who knows where they'll end up!" he assumed.

"I guess we won't know until we take a chance!" Sonic replied, "C'mon! Let's go!" Sonic called as he rushed inside the portal. Knuckles and Tails quickly exchanged glances before following him. After the last two entries, the portal weakened and the violet energy faded, the possibility of their return becoming _indefinite_.

* * *

><p>The portal led them into a flurry of warps and floating debris, eventually landing them in a bleak, colorless setting. Sonic landed on his feet while Knuckles clumsily landed on his bottom- as well as Tails. "What is this place?" the fox asked, shivering.<p>

"I dunno… it's kind of creepy, though, I'll give you that." Sonic replied.

"Why is there no color?" Knuckles blurted, "I can't even see the colors on you, Sonic, and that's hard to miss."

"That's easy to explain; where there is no light there is no color, it's a simple fact." Tails explained.

Sonic began walking around, staring at the floor and his surroundings. The entire area seemed to be filled with connecting lines and orbs. He wondered why Eggman's portal would lead them to an eerie place like this. The hedgehog felt his foot tap against an object; three to be exact. Sonic crouched down and picked up seemingly gray headsets, with an attached microphone to the side. "Don't people use these in concerts?" he asked aloud, turning to Tails who glanced at them.

"Uh, yeah! To sing, I guess… here, let me see." The twin-tailed fox took the headseats as Sonic handed the other one to Knuckles. "Yup! This is definitely a head and microphone set… that's strange. Why would these be found here?"

A sudden flash of lights caused the trio to jump in shock. Colors began flittering before their eyes, which was quite dizzying. Music began playing loudly over their ears, which was close to deafening to the naked ear.

"Sonic!" Tails shouted in pain, "What do we do?"

"Urgh! Put these things on!" he yelled back, putting on the headset quickly. Oddly enough, the music's volume became bearable, and an immediate shade retracted from them. Sonic took a _clear _look at the world around him now.

The lights were beautiful as they strode in different directions, flashing as if it were an electric-light show. Sonic noticed it created a path for them to run, and the music he heard earlier was on a sudden pause.

"Hey, guys, I think this microphone is to communicate!" Tails exclaimed, "This is so weird!"

"I'll say," Knuckles mumbled, "This is so weird! Why is this place full of lights and music?"

"It's pretty cool if you ask me!" Sonic chuckled, "Let's take a whack at that action, huh?" he gestured towards the path of red lights ahead of them.

"Well, if it means getting out of here, let's do it!" Knuckles replied, punching his fists together.

"Alright then!" Sonic dashed off, leaving the two to follow close on his trail. The music that was paused earlier began playing again; its rhythm quickening as Sonic's speed outranked the current frequency. Waves of light became visible as he ran, distracting Sonic momentarily.

"This place is… different," Sonic commented through the mic, "I think it knows the pace I'm running at!"

"Yeah, it seems the faster you go the music's tempo quickens, too!" Tails' voice responded, "Try moving slower!"

Sonic nodded as his previous break-out run turned into a jog, the pace of the song gradually slowing down. "Neat!"

The three friends ran for a while, looping around to what felt like a dark roller-coaster. Sonic eventually came to a stop once he heard the music finish, both Tails and Knuckles catching up by his side. "What happened?" the blue hedgehog asked, taking off his headsets. A gleam of light peered in front of them, and a golden, glowing key became visible through a faint mist. The key was shaped like a quarter-note, and it spun around slowly.

"It looks like a key or something!" Sonic stated slowly. He reached a hand to the key until another hand snatched it up abruptly, a familiar laugh echoing inside the area.

"Ohoho! Finders keepers!" Eggman's voice chortled, "See you!"

Sonic and his friends immediately chased Eggman, who could barely be seen. To their surprise, the area seemed to have an opening, a small thumbnail view of a city coming into view. "So this was a cave?" Knuckles asked blatantly, "That doesn't make sense!"

Sonic slowed down as he exited the supposed cave. The trip, upon exiting, arrived in a city of lights and sound. Everywhere they turned to was full of colorful lights and pumping music. The hedgehog groaned as he realized the loss of sight on Eggman. "Great," he muttered flatly, "He can be anywhere, now."

"Maybe some people here can help?" Tails suggested, "We might want to know what's up with this cave, though, and that key?"

"So; it looks like we have a couple of newbs here, huh?" a voice shouted out over the busy streets, the three of them turning to the caller.

"Who are you?"

* * *

><p><em>Authors Note: Yo! Hope you like the beginning of this story! Please review and tell me what'cha think! Thanks!<em>


	2. Chapter 2

CHAPTER TWO

"Who are you?" Sonic asked, eying the orange dog carefully. He wore a pair of headsets as well, although his were obviously upgraded and customized; while Sonic simply found his on the floor inside that cave. His gloves and shoes both seemingly a green color, as well as the designs on his headsets.

"My name's Tempo," the dog greeted coolly, "That was pretty wicked run you had in there; I've never seen someone run that fast before!" he laughed.

"Wait, how did you know we were in there?" Tails asked, "Were you spying on us?"

"No way, dude, why would I do that? Anyway, it's pretty obvious when someone is running around in the Sound Wave Cave; the lights flash so brightly that everyone in the city should know someone is in there! The music's speed is what made me realize the pace that you were running at- and _that _was fast." Tempo replied, smirking.

"Well, they don't call me Sonic for nothing!" the blue hedgehog remarked, placing his hands on his hips, "Pleasure to meet'ya, Tempo."

"All the same, bro," Tempo chuckled, gesturing to Tails and Knuckles, "And you guys?"

"My name is Miles Prower, but all my friends call me Tails!" the twin-tailed fox greeted shyly, twirling his tails around.

"Knuckles," the red echidna greeted simply, "Yo."

"All right, then! Now that we're all acquainted, ya gotta tell me how you just _ended up _in there. No one saw you guys walk in the SWC." Tempo said; his eyes shifting from the group of friends back to the 'Sound Wave Cave'. "Although I did see a fat guy running out of there with a _key_."

"Eggman!" Knuckles griped, "Do you know what that key is about, Tempo?"

"Well sure! It's actually just a rumor, so no one around here believes it…. but some say that after completing a song in the Sound Wave Cave, a key would appear! They say once you collect five keys, a treasure can be found deep inside the cave; pretty sweet, right?" Tempo asked giddily, "I get goose bumps just thinking about it! Anyways, people use that cave simply for sport. _Many _songs have been done by several challengers, but there was never a key before."

"I wonder if Eggman's portal has anything to do with this…" Tails murmured to himself quietly.

"So, you never did answer my earlier question." Tempo inquired jokingly.

"It's kind of a long story…" Sonic replied, "Think you have that kind of time?" he asked chuckling.

"Honestly, I have all the time in the world. Y'know what? Come with me to my younger sister's shop- maybe we can touch up on these headsets," the orange dog told them as he examined the headsets Sonic wore, "Those are pretty outdated, and they can totally use an upgrade." The three nodded, following Tempo as he rushed between relentless citizens.

* * *

><p>Tempo pushed open the doors to a small pawn shop; the shelves were full of parts and headsets in different models. Tails smiled as he took the most interest in surveying the hundreds of tools to tinker with.<p>

"Trill!" Tempo shouted as he gestured for Sonic, Knuckles, and Tails to hand other their headsets.

"Huh, it's so quiet in here… compared to the city outside." Sonic mused a he took the headsets off.

"It gets tiring to listen to all that music!" a squeaky voice answered in agreement, the head of a younger dog peering from behind a counter. "I've worked hard to make this place soundproof."

"It can become a little overwhelming." Knuckles grunted in agreement.

"Around these parts, you learn to get used to it… but if you're anything like my sister, you'll nag at your brother _constantly _asking him to move." The dog snorted, looking at the yellow dog sheepishly.

"Let me see," she mumbled, snatching the headsets from Tempo rudely. The orange dog shrugged and approached a book, full of headset models, and began searching for the headsets Sonic and his pals were using. He gasped as he found the model tucked away in the back of the book. "Trill! Those things are vintages!" he shouted, "Where did you get those?"

"We found them on the floor of that cave!" Sonic replied, "The music started playing and it nearly made me _deaf_. It's cool how those things tone it down a bit!"

"Yeah, they're made for that… these things are super _old_… but rare! Trill, y'think you can customize them a bit to have 'em blend in?"

The yellow dog, apparently named Trill, patted at her apron. "Well, yeah, that shouldn't be a problem. Hang tight, I'll give them to you later."

Sonic nodded and turned to Tempo. "So, I was going to tell you how I got here, right?"

Tempo grinned, his ears slightly twitching. "Yep! I'm all ears!"

"Well, that fat guy you mentioned earlier is actually an evil scientist, and he's the one who built a portal that led us here. He's known as Eggman where we come from, and he's just about the most _annoying _guy around." Sonic joked as he crossed his arms, "He took all seven of the Chaos Emeralds, and he used it to power that portal."

"Yeah," Tail piped in, "The systems were jammed because the emerald's power was too strong. Once we arrived, Sonic darted off with those headsets on."

"That's pretty cool… well, despite this fat guy Eggman constantly on your tail." Tempo chuckled.

"Yeah… you said something about 'after completing a song, a key appears', right?" Sonic asked.

"Yep," Tempo replied, "Good story."

"It's no story," Knuckles implied, "After Sonic noticed the music ended, this key showed up in front of his face. Eggman snatched it before he could, and took off."

"So it's true?" Tempo inquired excitedly, "No way!"

"Apparently so," Tails replied, "Although I find it pretty odd how keys didn't start showing up before Eggman invented this portal."

Sonic nodded in agreement. "It's pretty weird, considering how all the Chaos Emeralds disappeared… they must've scattered around this world as a result."

"Say, now that we know this key rumor exists, try not to let anyone else know. If everyone in this city knew that keys can now be obtained, there'll be a mess outside the Sound Wave Cave."

"That's another thing I wanted to ask you," Tails began, "How can that cave sense the movement of an individual? The music, too, seems unfathomable!"

"I can answer that," Trill spoke up as she exited the back room of her shop with the updated versions of their headsets, "The cave is basically enchanted. It displays sound to you as you run around in there, which explains all the lights. The music plays because it also senses your attitude and sense of direction. It's very popular amongst the teens that live around here."

"It's like the music plays with you," Tempo told them, "Totally sick."

"I have to admit, it felt like that the whole way!" Sonic said, smirking, "I could get used to a place like this."

"I wouldn't get cozy, though," Knuckles grunted, "Eggman is probably after the other keys in hopes of getting the treasure."

"Knuckles is right," Tails replied, "We shouldn't waste too much time."

"You could always split up and individually earn a key." Tempo suggested, "That way it'll be quicker!"

"Good idea!" Sonic rang, "Y'know, we could use all the help we can get."

Tempo grinned as Trill handed him back the headsets, now individually customized with designs and upgrades. "Sweet! I'd love to tag along!" The orange dog handed the headsets back to Sonic, Knuckles, and Tails.

"Thanks, Trill," Tempo said, patting her head.

"Yeah, yeah; you guys have fun." she muttered unamused.

The group was just about ready to leave until a bell dinged above the entrance to the store, welcoming a more than familiar black hedgehog and white bat, both geared up for the arrival to the world.

"_Shadow _and _Rouge_?"

* * *

><p><em>Author's Note: Ffft- what are they doing there? Stay tuned~ there's a perfectly good excuse for their arrival. :'D This chapter was meant to be short and explanatory, so, I'm sorry for the lack of action.<em>


	3. REWIND 1

REWIND 

_The following chapter takes place with Rouge and Shadow earlier that day. _

The ivory bat sat lazily in an office-styled chair, toying around with a jewel that shone a light blue. She caressed at it as if a newborn child and her teal blue eyes lifted to a man behind a burgundy desk, who looked at her earnestly. The bat slipped the jewel on her lap and leaned forward, resting her elbows on the desk. "Alright, what is it?" she asked, the words slipping out of her mouth smoothly.

"We have contacted you, Agent Rouge, and Agent Shadow to follow in pursuit of Eggman, who has collected all of the emeralds." The man replied meekly.

"Don't you think Sonic and his little friends would take care of something like that?" The bat, Rouge, asked discreetly as she unfolded her purple wings.

"There has been no trace of Sonic nor Tails and Knuckles, who we've assumed to have accompanied him. We need you and Shadow to investigate, and hope that Eggman has no intentions to attack our bases. Understood?" the man asked, "Hopefully our advance payment convinces you otherwise."

Rouge smirked, her glossed lip moving as she responded, "Why not? You had me at emeralds." The bat stood from her chair clenched the jewel, waving a goodbye. "Toodles." She chuckled as she stood tall in her heart-shaped boots, also adjusting her slick, black bodysuit.

"You're to meet up with Agent Shadow in front of the base; good luck." The man informed her strictly.

The bat nodded, exiting the door and facing him. "I'll be there."

* * *

><p>The black hedgehog stood in front of the damaged base, staring at the several remains of robots and machines scattered around the ash-tinted grass. He wondered if Sonic had already taken care of the situation, but G.U.N HQ had already confirmed the disappearance of the cobalt hedgehog. This made the ebony hedgehog suspicious.<p>

"Did you have all the fun without me already, Shadow?" a woman's voice asked facetiously, a soft thud following moments after the greeting.

The black hedgehog known as Shadow turned and faced her, shaking his head. "I didn't do this," he responded flatly, "I'd assume Sonic had this under control, but it seems as if he _failed_."

"Well, before we go on with presumptions, how about we do a little investigating?" the bat suggested, placing a hand on her hip and moving towards the dented doors.

Shadow nodded and followed after her, his eyes shifting towards a mass of rubble gathered in a corner. He wondered what went on as the two walked throughout a hallway. Shadow kicked a broken piece of glass out of his way, entering through what used to be the door to the control room. Rouge hovered over the debris and flew inside, surveying the area specifically for the Chaos Emeralds. When none were found, Rouge immediately lost interest in the case, however continued her investigation _less _willingly.

"What kind of contraption is that?" Shadow asked, approaching two arches that faced each other.

"I'm not sure… how about we hack into Eggman's computer? That should give us something." The bat said as she flew behind a desk where a large computer sat. Apparently, even after the earlier destruction, the computer was still functioning. Rouge assumed the direct combat was outside the base and within the halls. The bat typed in several phrases and codes into a small box, allowing her access into Eggman's blueprints for the machine.

"I have it up!" Rouge called, waving her finger to signal Shadow down. The black hedgehog leaped into the air and landed next to her, leaning close to the computer screen.

"It supposed to be a portal," the bat explained, scrolling down and reading the provided information, "It says here that it can transport someone to a different dimension."

"What could the Doctor benefit from something like that?" Shadow asked, finding the situation unclear.

"Who knows what goes through that thick, egg-head of his." Rouge replied amusingly.

"Hmph," Shadow huffed, "The Doctor wouldn't build something like this without a good reason…"

Rouge shrugged her shoulders, turning her head to face the portal. "It's no longer functioning… that means whatever was used to activate this portal is no longer here."

"The Chaos Emeralds," Shadow quickly answered, "He must've used their energy to power this."

Rouge gave a little laugh. "That explains the seven columns over there," she chuckled, pointing the columns where the emeralds sat earlier. Shadow examined the columns and the portal, processing different thoughts in his head.

"There is a possibility of a malfunctioning;" he eventually spoke, "The energy that the emeralds attain may have been proven to strong for the system."

Rouge nodded in agreement, tilting her head in a train of thought. "Maybe… perhaps we should swing this by G.U.N HQ, if anything they'll assign us elsewhere and we can forget about this."

"No," Shadow stated simply, "With the Sonic _and _the Doctor missing, things won't be settled around here."

Beeping sounds were heard as Rouge lifted her wrist to her mouth, "Agent Rouge is speaking."

"_Agent Rouge and Agent Shadow, abort the current mission and head for the headquarters immediately."_

"Understood," the bat replied coolly, looking to Shadow. "They have a little present for us, so it seems." Her voice flitted happily.

"Let's not waste time, then." Shadow responded emphatically, heading towards the exit of the control room. Rouge took one last look at the portal before spreading her wings and gliding after Shadow.

* * *

><p>After reporting the events to G.U.N HQ that involved Eggman's portal and his disappearance, as well as Sonic's and the emeralds', they sent the agents to a desolate room in a different building. The two sat patiently for the supposed 'specialist' that was to inform them of their new mission.<p>

"I wonder what's going on." The bat's voice spoke out, breaking the discreet silence. Shadow's ruby eyes narrowed towards her.

"Yeah," he replied calmly, "This is not like our other missions."

"A little change wouldn't hurt, I guess." The bat responded with little enthusiasm.

"Good evening, agents." A woman's voice greeted formally as she entered the dimly-lit room, dressed in suit combo specifically for women her age. She set down a broad briefcase on top of a desk and approached the two agents, who simply nodded at her in greeting.

"So, it looks like Eggman has his work cut out for him after all," she began firmly, "Cutting to the point, his machine functioned well with the help of the emeralds. However, our sources say their power overwhelmed the system and caused it to malfunction. How so? The intention of the contraption had changed." Shadow smirked, realizing his hunch was right.

"The intention you say?" Rouge questioned, "Wasn't the idea to transport someone to a different dimension?"

"That was a mere distraction file in his computer- the portal's intended purpose was to wipe Sonic out while he had the emeralds in his possession. He designed the machine to _appear _as a portal, as it turns out it was masking his true intentions." The woman responded, giving Rouge quite a shock.

"That actually sounds _evil _of him!" she mused, crossing her arms.

Shadow lifted his head and looked to the woman curiously. "Even with that information, how can the purpose of the machine just change?" he asked.

"This is where the specialist comes in. He examined it while you were traveling back here, and explains that there are some properties to the machine that could have altered once the Chaos Emeralds' energy surged into it. Details are to remain anonymous, and I'll be leaving the rest up to the man who will be assigning your mission." The woman spoke directly, stepping to the side as an older man, apparently a wolf, approached the agents.

"Agents," he greeted in a raspy voice, "The location of these individuals happen to be my home land. It can't be reached in any form of transportation; however you are more than able to teleport there."

The wolf approached the table and opened the briefcase brought in by the woman, and slipped a pair of headsets towards them. "These are the latest of their model," he explained, "They'll help you in blocking the… heh, harmonies of our world."

Rouge took a pair that was jeweled to her liking, examining them. "It kinda looks like headset and microphone combo used for singing." She pointed out, placing them on.

"The microphone is actually used for communication- since the frequency levels can be proven to be a bit high." The wolf answered, "I wish you luck on your mission. Return to the H.Q for further transportation; you have ten minutes to prepare."

With that last statement, the wolf and the woman exited the room.

"I'll meet you there, Shadow; I'm going to be changing into something more suitable." Rouge said as she stood up. Shadow simply nodded, grabbing the headset and leaving the room.

"Huh, not even a see you soon," Rouge snickered, following him out.

* * *

><p>Precisely ten minutes later, Rouge and Shadow reported their arrival to a fellow G.U.N agent. The bat now wore a black tube top accompanied with gray, designed shorts. He took them to a secluded room on the bottom floor; crackling noises could be heard as they approached the entrance.<p>

"Headphones on," the agent ordered before opening the door, "For your safety."

Shadow and Rouge placed them on, the shades retracting from the side of the headphones. The agent opened the door and stood to the side, the entrance automatically welcomed them to a noisy portal. "Your mission is to find the missing suspects, and report of them back here."

"Mission accepted," the agents replied simultaneously, Shadow walking through the portal first and Rouge following suit.

* * *

><p>The two found themselves racing along a path of red lights, the music in the background tearing up as the two Mobians expressed intensity and focus.<p>

"This music in the background corresponds with the lights, Shadow, and your pace!" Rouge said, struggling to keep up with him as she flew at his side.

"That's odd," he responded thoughtfully, "I've never witnessed this before."

"Neither have I, but the sooner we get this over with the sooner we can get out." The bat said as she landed on her feet and began to run. Shadow nodded as the two sped off, the entire space consumed of lights and loops.

Suddenly, the music abruptly stopped, and the lights flickered. "What happened?" Rouge asked quickly, "Everything just stopped!"

A shroud of mist began forming in a single area; a golden key that took the shape of a quarter note began rotating in the air. Rouge, attracted to nearly _anything _that glistened in the light, reached for it and grabbed it. "Hello gorgeous," she cooed as she scanned the object, "I like this place already."

Shadow shifted his attention towards a beam of light ahead of them. The light wasn't artificial, so he assumed there was an opening to the area. "It's a tunnel," he concluded after pondering, "Let's go." The black hedgehog skated quickly in the direction of the light with Rouge, seemingly distracted, following.

Rouge altered her direction forward. "Well, it looks like this was all a game." She said slyly, landing on the ground after a short flight. Shadow began examining the area for a sign of anyone familiar; to his luck, a blue hedgehog was the last to walk inside a local shop.

"Rouge, communicate with G.U.N immediately… tell them the suspects have been located." He said, walking quickly in order to catch up.

* * *

><p><em>Author's Note: So this is a rewind! It basically goes back to different character's point of view if they have a reason for being there. Later in the story, 1 rewind is left for the point of view of two other characters. Who do YOU think it is?<em>


	4. Chapter 3 and Sonic's Experience

CHAPTER THREE

"Shadow and Rouge," Sonic chuckled as he smugly grinned, "This is gonna to be good."

"Sonic," Rouge greeted, "Fox-boy and hothead." Knuckles immediately took the insult and lifted his fist in threatening way.

"Watch what you say, bat-girl!" he snapped, Rouge simply shaking her head in response. Sonic looked at the both of them curiously.

"What brings you by, huh?" the cobalt hedgehog asked, smirking.

"G.U.N mission," Rouge responded smoothly, "It was to locate you and the Doctor. The headquarters was raving about you two gone from Mobius."

"Well, we're here, so now _you _can leave." Knuckles snorted, directing his statement to Rouge specifically.

"Aw, that hurts, Knuckles, it really does. We came so far just to rescue you!" Rouge continued jocularly.

Tempo tapped Sonic on the shoulder lightly, whispering, "Isn't that a key in her hand?" Sonic nodded, giving a grin.

"That's a pretty fancy key you have there, Rouge." Sonic mused, pointing to the key clenched in her left hand.

"Bask in its glory, blue boy," Rouge snickered as she lifted it for a clearer view, " I found this little darling in that strange tunnel back there."

"So, you went into the Sound Wave Cave, too?" Tempo asked, "That means you went through a flurry of lights and music, right?"

Shadow decided to step out of his quiet moment and ask, "Yes. Could you explain the meaning of that?"

Sonic rolled his eyes and tapped his foot impatiently. "Tempo had already explained everything earlier; there are more of those keys to obtain, now." He told Shadow, "Sorry, but we have to get four more of these before Eggman can."

"There are more of these darlings?" Rouge asked, her ears perking up in attention.

"Yep, after five keys are obtained a treasure is unlocked in that cave." Tempo explained, "However we have yet to figure out what the treasure is."

"Eggman's probably headed over there, now." Tails urged, rather desperate.

"Heh! I'd like to see the song Egghead can pull off." Sonic kidded sarcastically, pushing the doors open to the shop.

Tempo, Knuckles, and Tails followed after him while Rouge and Shadow remained inside the shop. "This could be to our advantage, Shadow," Rouge began craftily, "Since we know where Eggman is, and what he's after, let's try to outdo him like those guys. It's the least we can do for taking the time out of our day off to come here."

Shadow smirked as he crossed his arms. "He deserves it," he agreed darkly. The two nodded at each other in assurance and both of them left the store.

* * *

><p>"There are five openings into this cave; they correspond to the number of keys," Tempo stated as he walked in front of them, "Which means if we were all to do this, we would have to split up. The quicker we get this done, the sooner we can obtain the keys and unlock the treasure."<p>

"Sounds good to me!" Sonic chuckled enthusiastically, heading towards the entrance on the far left. "Let's get this on a roll, whadd'ya say?"

The others nodded and spread out, all of them approaching an individual entrance. In an instant, the five took off in pursue of their own, musical adventure. Standing behind them was Shadow and Rouge, who eyed them mischievously.

"I'll go after Knuckle-head," Rouge apprised as she smirked covertly.

"As you wish," Shadow replied nonchalantly, "I'm after that orange dog." The two exchanged glances before rushing off into the desired entrances.

* * *

><p><span>SONIC'S EXPERIENCE<span>

The cobalt hedgehog walked inside the cave, smiling as a flash of lights welcomed him inside. Sonic watched as the wavering lights began taking forms of shapes and objects. To Sonic's surprise, they looked very similar to his world. A spark of green lights looped around the walls of the cave, and small, yellow lights were wrapped in small circles, almost looking like rings.

Sonic beamed as music began playing, what sounded like an electric guitar raring up to do a solo. "Let's dance!" Sonic declared heartily as he zoomed off and into the heavily lit atmosphere, the shades on his headsets retracting quickly.

Dings were heard as Sonic flew by the yellow lights shaped as rings, signifying that he had 'collected' them. The cobalt laughed as it reminded him of collecting rings back at Green Hill Zone, running around in a loop as green lights followed him quickly enough to catch up. The music in the background lifted Sonic's determination as the sound of the electric guitar began shredding different chords and notes.

The floor appeared as if it were checkered with orange and brown, baring much similarity to the platform he used to run on everyday. Sonic looked to his left, visible sound waves were pounding quickly as his speed quickened.

He suddenly saw a large, rainbow ring appear above him, almost as if he could jump right through it. Sonic smirked as crouched down and leaped high into the air, chimes echoing as he lifted through them. A bell rang once he completed his jump, the music becoming light for only a brief moment.

As soon as Sonic landed on the ground, the music picked up the pace again as he darted away. "Tempo's right," Sonic speculated as he continued to run, "This thing really knows who you are and how to express its light and music… and it plays with you!"

Waves of light began moving on the sides of him, the rush causing Sonic to accelerate at a much faster pace. A concentrated burst of light appeared in front of his eyes; Sonic squinted even with the shades before him; they began flaring yellow, white, blue, and red. Sonic grinned as a pixilated image began appearing before his eyes; it was Tails.

The electric guitar in the background began picking lightly as the image of Tails 'flew' next to Sonic on the wall beside him; "Hey 'buddy'!" he quipped as the figure waved hello. Another fusion of lights shone in front of him, the colors being red, green, yellow, and purple this time.

"Heh, Knuckles." Sonic mused as the figure glided on the other wall, shaking its fist. A final burst of light, reputedly farther away, began shimmering in the distance. What seemed to be an image of Eggman appeared; it waved around as if it were afraid.

Sonic grinned as the two pseudo versions of his pals advanced forward and attacked the figure, waiting for the final blow. Sonic hopped into the air, spinning into ball and spin dashing into 'Eggman', a boom of sound ending the lights and the music.

Sonic landed on the floor, kneeling down, and wondered if he had finished it; a shroud of mist flooding the area. '_That answers my question_!' Sonic thought as a golden key rotated in front of him.

* * *

><p><em>Author's Note: Yay! I got to post up Sonic's experience! It's rather short, I apologize, but I promise the other three experiences will be longer.<em>

_Experience Brief Explanation; Basically the next few chapters will be organized into 'experiences', which focuses on a single character as they race in the Sound Wave Cave. The cave will represent the important things in their lives. Later in the story, the true reason for the SWC will be revealed. Stay tuned to find out!_

_You can say I'm taking a lot of inspiration from Hollywood Studio's Rockin' Roller Coaster when I type out these chapters, lol. C'mon, Sonic racing in a place like that HAS to be cool.  
><em>


	5. Tails, Knuckles, and Tempo Experience

TAILS' EXPERIENCE 

The twin-tailed fox advanced into the cave skeptically, his bright blue eyes glistening as a spark of light accepted his presence. The colors of his adventure began with dark greens and grays, the setting the lights exhibiting an array of trees and bushes. This vaguely represented a forest, in his eyes.

Tails began flying in the air, with the help of his useful twin tails, and flew inside the supposed forest. A soft, ballad like-song began playing, the main instrument being a grand piano, as the fox progressed forward. A concentrated burst of light formed three little figures, one apparently represented himself and two, familiar but _horrible _figures.

The lights represented his past, being bullied for his mutation and smarts. The fox took in the moment solemnly, continuing his flight. However, a blast of sound surged into the cave, causing Tails to smile widely. A blue light cascaded from the ceiling to the floor as Tails continued forward, which represented Sonic and his kindness when the two first met.

A bustle of red, green, and blue lights danced around the cave, as if it was throwing a party with the young fox. "This place is… enigmatical… but enjoyable all the same!" he giggled gleefully, the chill of sheer excitement causing his fur to prickle.

The atmosphere felt suddenly light and weightless, as the cave gleaming blue- which stretched out into the distant city. The piano began playing lightly, but at a fast pace. The cave displayed an amazing view of what would be clouds and flying through the sky, white lights flickering amidst the glow of blue.

A little group of lights zoomed around the fox as he progressed deeper into the cave, the colors of the cave turning into grays and chromatic colors. Several lights took the shape of tools and widgets; they seemed to have created a little obstacle course for Tails to fly through.

The young fox laughed as he flew around a 'screwdriver' and flying over a 'hammer', and soon taking in the glories of his inventions. _'These lights tap into your emotions well, and it's as if it even knows your talents!' _Tails thought as a clear view of the lights, which took the form of his current biplane, _'Even the music is very suiting to what goes on around here…' _

His adventure spirals as he continued; literally _spiraling _as the fox was forced to run on the twisting platform, nearly dizzying Tails. Once the loops came to a stop, so did the music and the lights. Tails shifted his gaze towards a key that began rotating slowly, and smiled. "Great!" he cheered, grabbing the enchanted key and heading for the exit.

* * *

><p><span>KNUCKLES' EXPERIENCE<span>

Along with Rouge

Knuckles had stood in front of the entrance, expressing little interest in the journey he was about to embark. The sound of Eggman's laugh triggered his senses, causing the echidna to jerk forward and search for the obnoxious man behind the irritating laugh.

"Eggman!" he bellowed, holding up his fists.

The cave began flittering with lights, as if it mocked him for falling into its little trap.

"Say what- did you make that noise?" Knuckles snarled, the sound of a drum and crashing cymbals following suit.

"Very funny!" he grunted, crossing his arms. The drums he heard earlier began playing as a flash of green in the distance, spiking his curiosity quite a bit; he began running in that direction quickly.

Rouge followed him closely, snickering as she heard Knuckles' voice rambling. "He's talking to a _cave_," she mused lightly, the lights glittering along to catch her attention.

"Hm?" she hummed, looking around to see the lights taking the shape of jewels as a deep saxophone began playing. "Hah, I see what's going on here." Her voice spoke sleekly, flying into the air as the cave enlightened her senses to see the sparkling cave piquing her interest.

"Hey! That looks like the Master Emerald!" Knuckles proclaimed aloud, running towards the green lights from earlier. The lights indeed took the shape of the beautiful gem that's currently sitting in its place on Angel Island. Another group of lights made what seemed to be a smaller version of himself sitting in front of it, relaxing. Drums were being played a tad softer at this point.

Knuckles smirked, realizing how relaxed he used to feel when he sat in that spot. His peace was soon to be disturbed as the lights displayed a bright white, accompanied by pink, black, and purple; obviously the colors of a particular _bat_. The little iconic figure flew over the 'Master Emerald' picking it up and flying away, and the drums began beating hard inside the cave.

"ROUGE!" Knuckles roared; the real echidna racing after the fake, pseudo version of the sneaky bat. The real Rouge, still hot on his trail, laughed a little as to how gullible the red echidna can be.

"He never learns," she mused, her ears twitching as the saxophone began playing a lustful tune.

"I don't know if you can hear me or not, but cut it out!" Rouge chuckled, shaking her head. The saxophone continued to play, red lights beginning to form a trail that led to Knuckles' current running point. She rolled her aquamarine eyes and flew into the air, following the trail the cave purposely made for her.

"Rouge!" Knuckles continued to yell, following the mere huddle of lights 'flying' away with the 'Master Emerald'. Knuckles leaped into the air in hopes of catching the light, but of course they flickered off before he got the chance.

"Aw, what happened?" he asked in an annoyed tone, clenching his fist; a bright golden key began hovering above him.

"Oh! Well, if it weren't for all the running, I'd say that was pretty fun." He chuckled, stretching his hand up in order to grab the golden key. However, a faint saxophone began flowing through, confusing the echidna.

"I thought I was done!" he yelped, still attempting to reach for the key. A wave of wind brushed over Knuckles, and in an instant, the key vanished. To Knuckles' realization, Rouge flew above him with a smug grin tugging at her lips.

"A little too slow there, hothead!" she taunted jocularly, "It looks like I have two keys, now!"

"If you know what's good for you, bat, you'd give me back the key _I've _earned!" Knuckles threatened, preparing to leap into the air once more.

"I'd love to stick and chat but I've gotta fly," Rouge replied lustfully, giving a little wink. "Later." Her wings spread out wide as the bat glided down to the floor, away from Knuckles, and began zooming away from him.

"_Bat-girl_!" Knuckles hollered, "_Get back here_!" he demanded feverishly, chasing after the real Rouge more angrily than he did to the fake one.

* * *

><p><span>TEMPO'S EXPERIENCE<span>

Along with Shadow

Tempo, without hesitation, had already darted into the cave zestfully, the cave responding with a number of flashing, colorful lights, and the sound of a bass rumbling the ground. Unlike the previous two, his adventure began completely with action and enthusiasm.

A bright blue light zoomed passed him, a small 'barking' sound greeting him. "Heh, that sounds like Trill alright!" Tempo laughed, the blue light slowly turning into a red color. The orange dog smirked as he continued to run, not knowing the presence of another individual behind him.

Shadow glared at Tempo as he zoomed off into a fusion of colors. "Hmph," he grunted, "That seems a bit exaggerated."

The atmosphere suddenly changed; it turned into something both light and intense at the same time. It disarrayed Shadow, causing him to defensively stand his ground. The cave was pitch black for a few moments before twinkles of white lights altered his thoughts while the sound of an acoustic guitar began playing softly.

Soon thereafter, a cluster of brown lights began twinkling amongst what the cave represented as 'outer space'. Memories of the ARK flooded his brain, the ebony hedgehog frowning as the figure began flying away; Shadow curiously skated after it.

Tempo had looped his way through several obstacles as the cave tested his endurance, bringing much joy to the hyper dog. "This is way to fun!" he affirmed joyously, sliding down what seemed to be a railway. Tempo had encountered his small struggle in the past of his run, now relieving himself of it by carelessly tossing himself around the cave.

The cave helped expressed his liking for skateboard and music, the bass in the background playing crazily. Tempo enjoyed the feeling of rushing through a cave of lights.

The orange dog watched as his own colors began gathering on front of him, an iconic image of him taunting him to give chase. Tempo smirked as the thrust himself forward, following the little version of himself quickly.

"What is this?" Shadow asked himself sharply, the setting of 'outer space' now distorting and turning into a simple fury of lights, blinking around endlessly. The ebony hedgehog focused on the trail ahead of him, and began accelerating. A vague image of Rouge and a fellow G.U.N agent formed into the lights, both of them running along with him.

The flashing lights in the background obviously represented the infiltration of a base, as the music in the background became upbeat and tense; this pressured Shadow a bit.

Just when Shadow thought the two figures would collide into one, the lights flashed off, and the music faded.

"He must've completed his song," Shadow said to himself, "I'd better hurry."

Tempo grabbed the key happily, twirling it around his fingers. Before the dog could run off in search of the others, his face hit the side of what felt to be a rough, metal surface. "What the…" he murmured, using the glow the key secreted to light the current path.

A large robot stood in front of him, staring Tempo down with red, glowing eyes. "-TThat's a little too close for comfort!" he stammered, taking a few steps back. Tempo was usually quick to run, but he wasn't a fighter.

"_Now what?_" he thought helplessly, his ears hanging backwards in fear. Before the robot could attack, a surge of electricity began emitting from its core. Shadow had kicked the robot with such ferocity that it created a small opening.

"I'd run if I were you." Shadow told him quickly, "There's probably more of them."

"Y-Yeah no kidding," Tempo mumbled sheepishly, "T-Thanks."

"Don't thank me now," Shadow responded darkly, "You're going give me that key, first."

* * *

><p><em>Author's Note: Ooh, looks like Shadow wants to pick up a fight, lol. And robot oh my gosh! What's up with that? Stay tuned~<em>


	6. STORY ALERT

Hey what's up! So I've decided to continue this old plot and the story will be updated very soon. So yeah! Hope you'll be interested!


	7. Seven Treasures Secret

**Chapter 5; Seven Treasures Secret!  
><strong>

"What?" Tempo barked brashly, gripping the glowing key in his hands tightly. "Why? I earned this!" he continued defensively.

"It's either the key or your life, dog." Shadow sneered ominously, "Hand over the key, or you're at the mercy of the robots."

Tempo looked up at him disbelievingly for a moment until Shadow turned his back on him with robots marching towards them. "Fine!" the orange dog shouted in defeat, "You win... take it." he concluded disdainfully.

Shadow smirked slyly as he snatched the key from Tempo's hands, and proceeded to boost towards the robots with overwhelming speed. The force of his outbreak led the robots to collide together with Shadow projecting into the air with his narrowed, red eyes glaring the massive pile. As he slowly lifted to his peak in mid-air, he yelled, "I'd run if I were you!" to Tempo before diving head-first into the mountain of metal.

Without a minute to lose, Tempo charged towards the exit of the Soundwave Cave, his neon green eyes shrinking in an unsuspecting terror as the sound of a bursting explosion emanated through the cave walls. Only yards away, Tempo was pushed out of the cave with such ferocity that he landed just outside the cave, staring back at two, emerald-green eyes. "Sonic!" the dog muttered in weakness, "The robots- and Shadow!"

Sonic nodded gruffly before darting into the cave with high hopes of finding the ebony, hedgehog faker. "Shadow!" he called, "C'mon, you've done enough damage already! What're you up to?" he questioned loudly in a thicket of fog and stepping on scrap metal.

"I did not partake in the invasion of these robots," a dark voice responded, "Instead of assuming that it was my fault, consider the intentions of Eggman."

"Oh I know this was Eggman!" Sonic replied, "But you can't escape the explosion ordeal. That was you, and I didn't see a key in Tempo's hand, OR in Knuckles' hand when he came chasing after _Rouge _who held the key."

A small chuckle could be heard as Shadow finally made himself apparent to the blue hedgehog, who acknowledged his arrival with a defensive stance. "I don't have the time or persistence to keep up with you, hedgehog," Shadow began uncaring, "Yes, in addition to our mission, we're taking the keys, mainly to thwart Eggman."

Rather confused, Sonic eased back from his position. "Thwart, huh?" he snickered amusingly, "No matter how helpful that could be in this situation, y'gotta earn a key yourself. So, are you gonna give me back Tempo's key? C'mon, be a good sport, faker!" the cobalt hedgehog taunted.

Shadow's previous, lighter tone faded as his counterpart's final words rang about the cave. "Like I said, Sonic, I'm not going to bother with you or your team, I'm handling the situation my way, and if you stand in the way," he jeered flatly, "I won't hesitate to push you, or your friends out." Concluding his statement, Shadow skated away quickly, the light the key emitted fading as Shadow vanished into weakening fog.

Oddly enough, Sonic didn't give chase. Instead he retracted the shades of his headset and looked around bleakly. The walls of the cave no longer danced with color, and the corresponding music did not play. Everything seemed damaged deeply enough to be permanent. The orbs that once littered the cavern now lied on the cave floors, lost in a crowd of pieces of rusted metal. Not a single sound could be heard, not a guitar, nor a drum, nor a piano, nor a saxophone or keyboard, just _silence_.

Sonic, with a disapproving sigh, slowly made his way out of the cave the same way, _in silence._

* * *

><p>A wave of relief flooded the thoughts of every individual in Sonic's team as the blue hedgehog casually walked out, the only thing missing from his usual appearance being his trademark smile. At that point, everyone stared at him puzzled.<p>

"Sonic?" Tails questioned carefully, "Is everything alright?"

Sonic shook his head. "Shadow got away," he began reluctantly, "He dashed away with your key, Tempo, sorry."

Tempo waved a hand in assurance, "It's alright, we can always earn another one."

Knuckles punched his fists rashly, "No! We can't take that! Shadow is still out there, and so is Rouge! We have-!"

Sonic shook his head once more. "No Knux, let'em go for now. We have a bigger problem." he sighed as he pointed a finger to the Soundwave Cave, all of the caverns seemingly gray and smokey.

"That explosion, guys... I think it permanently damaged the cave. It's not interacting with anyone," Sonic stated sluggishly.

Knuckles paused, then shrugged his shoulders. "Too bad, I guess that treasure's history. Now we can focus on getting home." he said matter-of-factly.

Tempo's ears drooped in disbelief. "No, it has to work! Even worse than that, no more Soundwave fun- that was my stress-reliever, man!"

"Find another hobby! We _really_ need to get back! I need to get back to the Master Emerald!"

"Be reasonable, Knuckles," Tails brought up softly, "Let's think about this." The twin-tailed fox began pacing the ground, focused in thought. "Tempo, the legend says seven treasures? One being unlocked by five keys, correct?"

"Yep." Tempo responded sadly.

Tails continued with his deductive reasoning, and eventually came to a shocking conclusion. "Oh no!" he yelped, "We are relying on these treasures!"

"What do you mean, buddy?" Sonic asked curiously.

"Think about, Sonic," the fox turned eagerly the hedgehog, "Tempo said, when we met him, that no key was obtainable _before _we arrived! When we got here and completed a song, a key appeared!"

"What's your point?" Knuckles intruded rudely.

"Well, if Tempo says that there are SEVEN treasures, we have SEVEN Chaos Emeralds! The truth of the matter is, once we arrived and the Chaos Emeralds vanished, they turned into the prizes of this Soundwave game!"

The group shared a surprised gasp, and glanced at each other in a puzzling manner. Knuckles, being the first to speak, grunted, "Well great! That cave is broken, Shadow and Rouge took off with the keys, and Eggman is obviously up to no good. What in the world are we going to do without earning the keys?"

Tails then turned to the orange dog, who looked at him wearily due to his earlier experience. "What's up?"

"Where exactly do you take the keys when you collect five? Inside the cavern or...?"

Tempo nodded. "If you go deep into the cave, there should be a gate with five key slots. At least, that's the what the legend said... I can't be sure it's true. Anyway, it also says that it's a completely natural reaction when the keys show up that it opens- it says it's impossible to open it manually."

"At least that buys us time," Sonic mentioned casually, "That means Eggman, Shadow, and Rouge won't be able to open the cave."

Tails gasped again, giving everyone a spook. "Not unless we show up!" Tails pulled out his key, and pointed to Sonic. "We both have a key, Shadow and Rouge both have one, and Eggman stole one from earlier!"

"That makes five!" Tempo shouted, "You know what I think? Maybe..."

"They're waiting for us." Sonic continued, smirking. "It looks like we're gonna battle for this Chaos Emerald."

Knuckles looked to the both of them. "You guys go ahead, if Eggman or Rouge try to get away, I won't let'em get passed me without of fight!" he declared.

Sonic and Tails gave each other assuring nods, and proceeded inside the damaged Soundwave Cave.

* * *

><p><strong>A.N; Ooh, lots of stuff! What's gonna happen, who's gonna get the key? : D<strong>


	8. Author's Note

Hey guys! Inspiration has struck and I've found the motivation to work on this story again. I have a lot to write about, since I left y'all hanging right there in the beginning of the plot. I assure you it won't be anything less of what's already here.

If any of my old watchers are still around, I'm coming back FOR GOOD, so don't worry about disappearances. I won't leave 'till this story is finished.

Anyways, new or old, I hope you enjoy the rest of SS. I may repost the story to get it fresh in my head that includes more plot details. What do you think?

Would love to hear from you!

- Snazzy


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